First gear whine FJ 6MT

[DaveInDenver]

Quick clarification on the gearing. Coming more from the racing side of this stuff, I was thinking transmission internals when y’all said regear. We’re talking about completely different things, and I actually have no idea what diff ratios the previous owner was running They had this truck set up with the lift, 33s, a CB radio and a reallllllly rusty hitch when I bought it from Toyota in May ‘25, so it’s entirely possible they already regeared the diffs to compensate. How would I find out?

Good leads on the clamshell bearing and inspection plate. I’ll pull up some YouTube audio and see if it matches what I’m hearing. On the lift and tires, the truck truly ran fine for 8 months with this exact setup before the whine started. It appeared specifically when the master cylinder failed in January, not gradually over time, so it’s hard to blame the setup. No fluid leaks that I know of, and Toyota did replace one CV under warranty. On the TOB contact, that relationship gets re-established every time the bellhousing comes off, which happened twice now. Should have been corrected both times, right?

Regearing Aisin transmissions isn't typically done. Not even sure it's possible. Sometimes you'll see complete transmission swaps but that's very unusual in newer trucks with RA6x unless it's a whole drivetrain and probably an engine swap. Some people go to a part time transfer (VF2B variant) in their FJC, usually because they're doing a solid axle swap.

Some Toyota transfer cases can be regeared but not in the case of the VF4B you have.

Normally when we say "regear" we're talking about your axle ratios.

You can figure this out pretty easily.

• Chock the front wheels
• Jack up one side of the rear of truck (you only want one tire to spin)
• Put a mark on the tire, a piece of tape or chalk line for example
• Put a similar mark on the driveshaft or pinion flange, whatever you can see
• Turn the tire two complete revolutions* while counting the number of revolutions the driveshaft goes through

Go slow and be precise. The pinion should in your case go through almost exactly 4 complete revolutions, 3.9 to be exact. If it goes through more or less then you have to estimate how much. There are only so many possibilities. Toyota used 3.73 in my truck so the pinion would go through 3 and 3/4 revolutions for two of the lifted tire.

But almost no one goes taller, we all go shorter to get a slower crawl speed and compensate for taller tires.

Other possible combination you may see in a Toyota 8" differential are 4.10, 4.30, 4.56, 4.88 or 5.29.

It's unlikely someone would go to the trouble to use 4.10, which is barely changing. So most likely is 4.56 or maybe 4.88 if it's been regeared. So you'll see close to 4 and a half driveshaft turns for 4.56 and 4 and 3/4 for 4.88.

The way you describe your operation would lead me to believe you still have stock axle gearing. The first gear in your RA61 is 4.171, which isn't bad but not granny either. The truck came with about a 30.5x10.5 or so (say a 265/70R16) so your 33" tires are probably around 7% to 8% larger in circumference and that's usually enough to notice. More so when you factor in the increased weight of the larger tire.

Each time the transmission was pulled a fair amount of stuff was touched, so the bearing as well as pedal height and throw probably should have been inspected. It's not a major change, though. But they had to remove the slave cylinder, which means where it sits on the housing and relative to the fork might move a little. That's why there's the inspection port.

This is a Toyota dealer doing the work? They ought to have a pretty good idea of what they're doing.

*If you want to double check and you have an e-locker, you could raise both tires, lock the diff and repeat doing one revolution. With the diff locked rather than open both tires will spin in the same direction and the driveshaft will turn the numerically correct number of times.

By the way, if there's any question it might not be a bad idea to do this on the front, too, to verify that both axles are geared the same. Although with full time 4WD you'd notice quickly if that wasn't the case.

 

[shovelhead]

Regearing Aisin transmissions isn't typically done. Not even sure it's possible. Sometimes you'll see complete transmission swaps but that's very unusual in newer trucks with RA6x unless it's a whole drivetrain and probably an engine swap. Some people go to a part time transfer (VF2B variant) in their FJC, usually because they're doing a solid axle swap.

Some Toyota transfer cases can be regeared but not in the case of the VF4B you have.

Normally when we say "regear" we're talking about your axle ratios.

You can figure this out pretty easily.

• Chock the front wheels
• Jack up one side of the rear of truck (you only want one tire to spin)
• Put a mark on the tire, a piece of tape or chalk line for example
• Put a similar mark on the driveshaft or pinion flange, whatever you can see
• Turn the tire two complete revolutions* while counting the number of revolutions the driveshaft goes through

Go slow and be precise. The pinion should in your case go through almost exactly 4 complete revolutions, 3.9 to be exact. If it goes through more or less then you have to estimate how much. There are only so many possibilities. Toyota used 3.73 in my truck so the pinion would go through 3 and 3/4 revolutions for two of the lifted tire.

But almost no one goes taller, we all go shorter to get a slower crawl speed and compensate for taller tires.

Other possible combination you may see in a Toyota 8" differential are 4.10, 4.30, 4.56, 4.88 or 5.29.

It's unlikely someone would go to the trouble to use 4.10, which is barely changing. So most likely is 4.56 or maybe 4.88 if it's been regeared. So you'll see close to 4 and a half driveshaft turns for 4.56 and 4 and 3/4 for 4.88.

The way you describe your operation would lead me to believe you still have stock axle gearing. The first gear in your RA61 is 4.171, which isn't bad but not granny either. The truck came with about a 30.5x10.5 or so (say a 265/70R16) so your 33" tires are probably around 7% to 8% larger in circumference and that's usually enough to notice. More so when you factor in the increased weight of the larger tire.

Each time the transmission was pulled a fair amount of stuff was touched, so the bearing as well as pedal height and throw probably should have been inspected. It's not a major change, though. But they had to remove the slave cylinder, which means where it sits on the housing and relative to the fork might move a little. That's why there's the inspection port.

This is a Toyota dealer doing the work? They ought to have a pretty good idea of what they're doing.

*If you want to double check and you have an e-locker, you could raise both tires, lock the diff and repeat doing one revolution. With the diff locked rather than open both tires will spin in the same direction and the driveshaft will turn the numerically correct number of times.

By the way, if there's any question it might not be a bad idea to do this on the front, too, to verify that both axles are geared the same. Although with full time 4WD you'd notice quickly if that wasn't the case.

Got it. Okay, how important is this for diagnosing the whine? I ask because my driveway is super sloped, and so I'd have to find some random flat spot to do this, and I've never jacked up this vehicle up before. I'm also considering contacting Toytec since I don't fully trust Toyota after they put the wrong gear oil into the new transmission, dismissed my clutch concerns for almost a year, and they flatly stated that the TSB regarding the aluminum quill on the bell housing did not apply to my model year. Which... the TSB may have technically ended prior to my model year, but the underlying design flaw was still continued into my model year FJ smh.

 

[DaveInDenver]

Knowing gear ratios aren't important to the gear whine, if that's what it is. I'm not convinced what you're hearing is really whine but some sort of yet indefinite mechanical noise. Gear whine is a fairly specific thing and you really can't "fix" it without addressing the gear faces and shims, some which is just the way the gears are cut in the end. All gears could be more noisy if they're new breaking in, exceptionally worn out, the lube is low.

Like the transmission and t-case, axle gears wouldn't just suddenly start making offensive gear meshing noise. For the bulk of their life they just make the noise they make.

Something has to change, a tooth breaks, bearings fail, synchros wear out, you run dry, etc for a sudden change in sounds. It can happen. Yet you changed the suspected offending element, so it shouldn't be the clutch, transmission gears or bearings. Unlikely, not impossible though, to have a defective new part or subsequent damage due to a mistake. You'd think none of this is the first time for these mechanics on this. The issue goes back to 2005 on the Tacoma.

I don't know anything about the TSB year updates on the clutch. If it doesn't cover your model year then it means it's not a potential warranty issue but like you say at this point the issue is at least a decade old and endemic to all RA6x and they should know that. Why it would matter if you're paying for the work I have no idea.

That said, the TSB isn't really helpful on the wear and says it's normal without defining any criteria to judge severity. A little bit isn't an issue so ultimately it's left to the experience of the mechanic to know if the grooving is bad or not. I'd think the dealer would not be interested in aftermarket solutions here such as the repair sleeve.





FWIW I also attached the most recent revision of the needle bearing TSB for your reference. Lift is a red flag for suspecting that IMO.

I went from the stock needle bearing to the ECGS sintered bushing and recently went back to the needle bearing. I didn't get any more miles (about 50K) from the ECGS solution than I did from the stock needle bearing ultimately. It's more of PITA to get the ECGS bushing out than the needle bearing so the repair is easier doing it the stock way.

BTW, you mentioned a replacement CV axle. I will mention that when you're pulling and inserting the CV axle it's possible to catch the lip of the shaft on the needle bearing, which can pull the needles from the cage. This isn't speculation, I saw it happen first hand. You don't want this to happen. If it did it could explain this potentially. The axle would wobble, it would make pretty bad noise.

Just saying.

 

[shovelhead]

Knowing gear ratios aren't important to the gear whine, if that's what it is. I'm not convinced what you're hearing is really whine but some sort of yet indefinite mechanical noise. Gear whine is a fairly specific thing and you really can't "fix" it without addressing the gear faces and shims, some which is just the way the gears are cut in the end. All gears could be more noisy if they're new breaking in, exceptionally worn out, the lube is low.

Like the transmission and t-case, axle gears wouldn't just suddenly start making offensive gear meshing noise. For the bulk of their life they just make the noise they make.

Something has to change, a tooth breaks, bearings fail, synchros wear out, you run dry, etc for a sudden change in sounds. It can happen. Yet you changed the suspected offending element, so it shouldn't be the clutch, transmission gears or bearings. Unlikely, not impossible though, to have a defective new part or subsequent damage due to a mistake. You'd think none of this is the first time for these mechanics on this. The issue goes back to 2005 on the Tacoma.

I don't know anything about the TSB year updates on the clutch. If it doesn't cover your model year then it means it's not a potential warranty issue but like you say at this point the issue is at least a decade old and endemic to all RA6x and they should know that. Why it would matter if you're paying for the work I have no idea.

That said, the TSB isn't really helpful on the wear and says it's normal without defining any criteria to judge severity. A little bit isn't an issue so ultimately it's left to the experience of the mechanic to know if the grooving is bad or not. I'd think the dealer would not be interested in aftermarket solutions here such as the repair sleeve.





FWIW I also attached the most recent revision of the needle bearing TSB for your reference. Lift is a red flag for suspecting that IMO.

I went from the stock needle bearing to the ECGS sintered bushing and recently went back to the needle bearing. I didn't get any more miles (about 50K) from the ECGS solution than I did from the stock needle bearing ultimately. It's more of PITA to get the ECGS bushing out than the needle bearing so the repair is easier doing it the stock way.

BTW, you mentioned a replacement CV axle. I will mention that when you're pulling and inserting the CV axle it's possible to catch the lip of the shaft on the needle bearing, which can pull the needles from the cage. This isn't speculation, I saw it happen first hand. You don't want this to happen. If it did it could explain this potentially. The axle would wobble, it would make pretty bad noise.

Just saying.

Super appreciate all that. I asked Toyota if they could implement that aftermarket sleeve and got the big no, bc the transmission swap was covered under warranty. I did get a pic of my new bell housing, and asked for pics of the old bell housing (showing the condition of the quill) and this is all they gave me (attached). I had to explain several times that the TOB sits on the quill and needs to be removed for the full quill to show, to no avail. So all this pic shows is the beat up input shaft, the shiny new TOB that came with the Mar '26 clutch job sitting atop the old worn quill, the chewed up quill collar, but not the full quill. And all of this was tossed out when the new transmission (which came with its own brand new TOB + fork in Apr '26) arrived. The service advisor DID show me pics of the outgoing quill eventually, in person, saying I would receive them in email shortly, and they never came. But I saw it--it had horizontal scoring where the TOB clearly held a couple positions, spinning in place, and wore some deep grooves into the aluminum. Ouch. I have 400 miles left before this warranty expires, and am not sure whether to have another Toyota dealer check things out before my warranty expires, or to just let this go.

 

[KC Masterpiece]

I am going to toss a question in here having previously owned an FJ. Not a MT. I had a sudden whine on mine after a driveline service once. I looked all over for the source and in the end it turned out the front diff fluid level was quite low.

Have you checked your diff and transfer case fluid levels? Im guessing yes, but I have not seen that mentioned anywhere in the thread.

 

[shovelhead]

I am going to toss a question in here having previously owned an FJ. Not a MT. I had a sudden whine on mine after a driveline service once. I looked all over for the source and in the end it turned out the front diff fluid level was quite low.

Have you checked your diff and transfer case fluid levels? Im guessing yes, but I have not seen that mentioned anywhere in the thread.

Thank you for thinking of this. Transfer case just got a fluid swap but I will see if I can figure out how to check the front & rear diffs myself.

 

[shovelhead]

Update. Took it to an offroad specialist shop today, and they suspect that the sound might be coming from the drive belt tensioner/idle pulley. If that's plausible, then I'm a little confused as to why the sound would start when I push the clutch in, and cut immediately when I pull the shifter from 1st into neutral, with the clutch still in. Any thoughts?

 

[KC Masterpiece]

Thank you for thinking of this. Transfer case just got a fluid swap but I will see if I can figure out how to check the front & rear diffs myself.

Guessing the shop checked it, but its as easy as it gets. Open the fill plug and stick your finger in. Oil level should be right at the bottom of the fill plug.

 

[Rzeppa]

Update. Took it to an offroad specialist shop today, and they suspect that the sound might be coming from the drive belt tensioner/idle pulley. If that's plausible, then I'm a little confused as to why the sound would start when I push the clutch in, and cut immediately when I pull the shifter from 1st into neutral, with the clutch still in. Any thoughts?

What's the name of the shop so we can be sure to never go there?

 

[DaveInDenver]

Update. Took it to an offroad specialist shop today, and they suspect that the sound might be coming from the drive belt tensioner/idle pulley. If that's plausible, then I'm a little confused as to why the sound would start when I push the clutch in, and cut immediately when I pull the shifter from 1st into neutral, with the clutch still in. Any thoughts?

It's plausible (and probably likely, my original went at around 100K) that the tensioner is making noise but I can't imagine any way to link it to pushing the clutch. Even if the motor mounts are shot and the whole drivetrain is shifting it can't change the belt tension.

Now that said it can make a grinding sound, actually not too different than the release bearing I suppose. Not sure I'd call it a whine.

On mine it was easy to diagnose. With the engine running, lift the hood and stare at the front and listen for a dry bearing sound. If you hear it you can pinpoint it with a long socket extension or dowel rod or something like that. Hold the rod to your ear and touch the bolt in the middle of the tensioner. It'll be the same dry bearing sound except about ten times as loud.

It takes about an hour to replace it, the two dummy pulleys and the belt. It's not difficult.

 

[shovelhead]

It's plausible (and probably likely, my original went at around 100K) that the tensioner is making noise but I can't imagine any way to link it to pushing the clutch. Even if the motor mounts are shot and the whole drivetrain is shifting it can't change the belt tension.

Now that said it can make a grinding sound, actually not too different than the release bearing I suppose. Not sure I'd call it a whine.

On mine it was easy to diagnose. With the engine running, lift the hood and stare at the front and listen for a dry bearing sound. If you hear it you can pinpoint it with a long socket extension or dowel rod or something like that. Hold the rod to your ear and touch the bolt in the middle of the tensioner. It'll be the same dry bearing sound except about ten times as loud.

It takes about an hour to replace it, the two dummy pulleys and the belt. It's not difficult.

I wish I could post the video of the sound here, argh. But yeah, the internet said it would take 1 hour for just the belt, and 2 hours if you include the pulley swap, and then you add onto that the fact that I have NEVER successfully done anything on a car before (managed to successfully mess up my Mustang's brakes and power steering in my 20s though lol)... I estimate 2 days for me

 

[shovelhead]

But in all seriousness, can you all recommend a good shop, in the south metro preferably? Because the shop that thinks it’s the serpentine belt tensioner and idle pulley has like 4.8 stars on Google.

 

[DaveInDenver]

Japanese Auto in Wheat Ridge (see if you can get Joe Rasavi).

Toy Car Care in Centennial.

You may pay for an hour but it's maybe 6 minutes and 14 seconds of actual work. You need a 10mm socket you remove the plastic cover if you still have it, a 14mm socket wrench and a 5/16 pin punch.

 

[Crash]

Japanese Auto in Wheat Ridge (see if you can get Joe Rasavi).

Toy Car Care in Centennial.

You may pay for an hour but it's maybe 6 minutes and 14 seconds of actual work. You need a 10mm socket you remove the plastic cover if you still have it, a 14mm socket wrench and a 5/16 pin punch.

X2 on Joe.

 

[shovelhead]

Japanese Auto in Wheat Ridge (see if you can get Joe Rasavi).

Toy Car Care in Centennial.

You may pay for an hour but it's maybe 6 minutes and 14 seconds of actual work. You need a 10mm socket you remove the plastic cover if you still have it, a 14mm socket wrench and a 5/16 pin punch.

Not exactly south metro haha but thank you, I will call and ask for Joe! I am definitely not taking it back to Toyota, and my warranty runs out in 20 miles anyway. I do believe that I need to get the serpentine and idle pulley situation fixed, because I think it might be causing noise when I am on the highway at speeds, but I really can’t wrap my head around how it would be causing this first gear whine.

 

[KC Masterpiece]

You could also get someone with a 40 or 60 to take you out for a quick spin around and you will no longer notice your gear whine.

 

[shovelhead]

You could also get someone with a 40 or 60 to take you out for a quick spin around and you will no longer notice your gear whine.

Haaaa. I’m hoping to attend next month’s meetup, so maybe that will happen lol!

 

[DaveInDenver]

Haaaa. I’m hoping to attend next month’s meetup, so maybe that will happen lol!

Could also get the 4-1-1 on other RA6x FJC and Tacoma and have owners listen to yours to get a wider range of opinions on what it might be and if it's serious or not.

 

[shovelhead]

Could also get the 4-1-1 on other RA6x FJC and Tacoma and have owners listen to yours to get a wider range of opinions on what it might be and if it's serious or not.

Word! Definitely looking forward to meeting actual humans. I’ve been doing this all alone so far, figuring out the issues, advocating for myself w/ Toyota, and even hitting some trails alone etc. It would be nice to have a community.

 

[KC Masterpiece]

There is also a big FJC community on the front range. I bet you could get some good info on the FJ cruiser forum.